Lens based antenna for super high capacity wireless communications systems

ABSTRACT

An antenna includes a stack of cylindrical lenses combined with feed elements to provide multi-beam coverage for a given wireless communication sector. Each cylindrical lens disc has approximately the same height as the feed elements being used with the lens. To overcome the problem of interference from cables and opposing feeds, feed elements are placed around the lens. The cylindrical lenses are stacked such that a small gap exists between each pair of adjacent cylindrical lenses, allowing for cable lines to pass through between the pair of the cylindrical lenses, and thus removing interference for 360 degree coverage. Cable lines are arranged such that they only traverse the portion of the circumferential surfaces of the cylindrical lenses that do not interfere with the field of view of the RF signals generated by the corresponding feed elements.

This application claims the benefit of U.S. provisional application No.62/201,512 filed Aug. 5, 2015. This and all other referenced extrinsicmaterials are incorporated herein by reference in their entirety. Wherea definition or use of a term in a reference that is incorporated byreference is inconsistent or contrary to the definition of that termprovided herein, the definition of that term provided herein is deemedto be controlling.

FIELD OF THE INVENTION

The field of the invention is radio frequency antenna technology.

BACKGROUND

The following description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

Wireless networks providing voice and data services are constantlyexpanding capacity to keep up with demand. Infrastructure build-out hastraditionally comprised of adding more base stations and accompanyinghardware at existing sites and adding new sites. State of the artantenna solutions are based on directional antennas utilizing radiatingelements and a reflector. For applications where there are high datatraffic requirements, multi-beam antenna solutions are becomingincreasingly important. Multi-beam antennas are able to cover a widearea of coverage depending on the requirement and the antenna design (upto 360 degrees) while providing multiple beams for a given frequency orfrequency range. Aside from traditional phased-array solutions, whichhave key drawbacks such as scope of coverage (can provided limitedcoverage, i.e., not 360 degrees), size and individual beam performance(degradation of gain on side beams), there are possibilities of using aRF lens approach.

One proposed solution is using cylindrical RF Lenses which are capableof providing multiple beams for different sector coverage. However,using a cylindrical lens approach can present challenges for providing360 degree coverage as when feeds (emitters) are traditionallypositioned around the circumference of the cylinder, there isinterference from opposing feeds (feeds placed directly opposite eachother on the cylinders circumference).

Furthermore this approach is limited in providing a narrow verticalbeam. Due to the shape of the cylinder, only the horizontal resultantbeam-width of the feed is affected by the cylinder while the verticalbeam-width remains unchanged. Another approach is to use a sphericallens such as a Luneburg Lens, which, due to its symmetrical sphericalshape equally narrows both the resultant horizontal and verticalbeam-width of the feeds placed around the circumference of the Lens.However even though this approach provides reduced interference fromopposing feeds (based on the size of the sphere used, the resultant beamwould be several times larger than the opposing feed, thus reducing itsinterference), interference still exist and the size and cost of thesolution provide drawbacks to this approach. Aside from the feedsthemselves, the required cable lines and any support structures furtheradd to interference for both lens approaches. Therefore the challenge isproviding a 360 multi-beam solution with limited interference fromfeeds, cable lines and any support structures.

Thus, there is still a need for an effective and efficient antenna foruse with extremely high capacity wireless communication systems.

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application werespecifically and individually indicated to be incorporated by reference.Where a definition or use of a term in an incorporated reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein applies and the definitionof that term in the reference does not apply.

SUMMARY OF THE INVENTION

The inventive subject matter provides apparatus, systems and methods inwhich a stack of cylindrical lenses are combined with feed elements (orarrays of feed elements) to provide multi-beam coverage for a givenwireless communication sector. The lens can be constructed from multiplecylindrical lenses where each cylindrical lens disc has approximatelythe same height as the feed elements being used with the lens. Toovercome the problem of interference from cables and opposing feeds,feed elements are placed around the lens (feeds facing each other onopposite sides). Alternatively, feed elements can be arranged around acylindrical lens section to cover approximately 120 degrees of field ofview. Three such cylindrical lenses can then be stacked (combined) alongthe axes of the cylindrical lenses to create 360 degree coverage. Thecylindrical lenses are stacked such that a small gap (about the width ofa cable) exists between each pair of adjacent cylindrical lenses,allowing for cable lines to pass through between the pair of thecylindrical lenses, and thus removing interference for 360 degreecoverage. Cable lines are arranged such that they only traverse theportion of the circumferential surfaces of the cylindrical lenses thatdo not interfere with the field of view of the RF signals generated bythe corresponding feed elements.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary antenna system of some embodiments thatincludes a stack of cylindrical lenses.

FIG. 2 illustrates an example cable arrangement of some embodimentsthrough the stack of cylindrical lenses.

DETAILED DESCRIPTION

Throughout the following discussion, numerous references will be maderegarding servers, services, interfaces, engines, modules, clients,peers, portals, platforms, or other systems formed from computingdevices. It should be appreciated that the use of such terms is deemedto represent one or more computing devices having at least one processor(e.g., ASIC, FPGA, DSP, x86, ARM, ColdFire, GPU, multi-core processors,etc.) configured to execute software instructions stored on a computerreadable tangible, non-transitory medium (e.g., hard drive, solid statedrive, RAM, flash, ROM, etc.). For example, a server can include one ormore computers operating as a web server, database server, or other typeof computer server in a manner to fulfill described roles,responsibilities, or functions. One should further appreciate thedisclosed computer-based algorithms, processes, methods, or other typesof instruction sets can be embodied as a computer program productcomprising a non-transitory, tangible computer readable media storingthe instructions that cause a processor to execute the disclosed steps.The various servers, systems, databases, or interfaces can exchange datausing standardized protocols or algorithms, possibly based on HTTP,HTTPS, AES, public-private key exchanges, web service APIs, knownfinancial transaction protocols, or other electronic informationexchanging methods. Data exchanges can be conducted over apacket-switched network, a circuit-switched network, the Internet, LAN,WAN, VPN, or other type of network.

As used in the description herein and throughout the claims that follow,when a system, engine, or a module is described as configured to performa set of functions, the meaning of “configured to” or “programmed to” isdefined as one or more processors being programmed by a set of softwareinstructions to perform the set of functions.

The following discussion provides example embodiments of the inventivesubject matter. Although each embodiment represents a single combinationof inventive elements, the inventive subject matter is considered toinclude all possible combinations of the disclosed elements. Thus if oneembodiment comprises elements A, B, and C, and a second embodimentcomprises elements B and D, then the inventive subject matter is alsoconsidered to include other remaining combinations of A, B, C, or D,even if not explicitly disclosed.

As used herein, and unless the context dictates otherwise, the term“coupled to” is intended to include both direct coupling (in which twoelements that are coupled to each other contact each other) and indirectcoupling (in which at least one additional element is located betweenthe two elements). Therefore, the terms “coupled to” and “coupled with”are used synonymously.

In some embodiments, the numbers expressing quantities of ingredients,properties such as concentration, reaction conditions, and so forth,used to describe and claim certain embodiments of the inventive subjectmatter are to be understood as being modified in some instances by theterm “about.” Accordingly, in some embodiments, the numerical parametersset forth in the written description and attached claims areapproximations that can vary depending upon the desired propertiessought to be obtained by a particular embodiment. In some embodiments,the numerical parameters should be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of some embodiments of the inventivesubject matter are approximations, the numerical values set forth in thespecific examples are reported as precisely as practicable. Thenumerical values presented in some embodiments of the inventive subjectmatter may contain certain errors necessarily resulting from thestandard deviation found in their respective testing measurements.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

Unless the context dictates the contrary, all ranges set forth hereinshould be interpreted as being inclusive of their endpoints andopen-ended ranges should be interpreted to include only commerciallypractical values. The recitation of ranges of values herein is merelyintended to serve as a shorthand method of referring individually toeach separate value falling within the range. Unless otherwise indicatedherein, each individual value within a range is incorporated into thespecification as if it were individually recited herein. Similarly, alllists of values should be considered as inclusive of intermediate valuesunless the context indicates the contrary.

All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. The use of any and all examples, or exemplary language (e.g.“such as”) provided with respect to certain embodiments herein isintended merely to better illuminate the inventive subject matter anddoes not pose a limitation on the scope of the inventive subject matterotherwise claimed. No language in the specification should be construedas indicating any non-claimed element essential to the practice of theinventive subject matter.

Groupings of alternative elements or embodiments of the inventivesubject matter disclosed herein are not to be construed as limitations.Each group member can be referred to and claimed individually or in anycombination with other members of the group or other elements foundherein. One or more members of a group can be included in, or deletedfrom, a group for reasons of convenience and/or patentability. When anysuch inclusion or deletion occurs, the specification is herein deemed tocontain the group as modified thus fulfilling the written description ofall Markush groups used in the appended claims.

The inventive subject matter provides apparatus, systems and methods inwhich an antenna having multiple cylindrical lenses and feed elements(or arrays of feed elements) to provide multi-beam coverage for a givenwireless communication sector. The feed element is an electronic devicefor emitting RF signals, detecting RF signals, or both. In someembodiments, the feed elements are disposed near the surface of thecylindrical lenses (e.g., within 5 inches, preferably within 2 inches ofthe surface of the lens). Preferably, each lens element also includes amechanism for moving the feed element along the surface of the lens inorder to adjust the angles and direction in which the feed elementemits/receives the RF signals. Details of this mechanism for moving thefeed elements can be found in a co-owned U.S. patent application Ser.No. 14/958,607, titled “Spherical Lens Array Based Multi-Beam Antennae,”filed Dec. 3, 2015, which is incorporated in its entirety herein byreference.

A cylindrical lens is a lens with an exterior surface having a shape of(or substantially having a shape of) a cylinder having a ellipticalcircumference and a height. As defined herein, a lens with a surfacethat substantially conform to the shape of a cylinder means at least 50%(preferably at least 80%, and even more preferably at least 90%) of thesurface area conforms to the shape of a cylinder. Examples ofcylindrical lenses include a cylindrical-shell lens, drum-shaped lens (asphere with the top and bottom portions cut off and flattened), etc. Thecylindrical lens can include only one layer of dielectric material, ormultiple layers of dielectric material. A conventional Luneburg lens isa spherically symmetric lens that has multiple layers inside the spherewith varying indices of refraction.

In some embodiments, the antenna can include multiple cylindrical lensesthat are stacked together along the axes of the cylindrical lenses. Insome embodiments, each cylindrical lens in the stack has approximatelythe same height as the feed elements associated with the lens. Toovercome the problem of interference from cables and opposing feeds ifemitters were simply placed around the lens (feeds facing each other onopposite sides), feeds for each cylindrical lens can be arrange around asection of the lens to cover approximately 120 degrees field of view inthe horizontal plane (a plane that is perpendicular to the axis of thecylindrical lens and parallel to the ground). Three such cylindricallenses can then be stacked (combined) against each other along the axesof the cylindrical lenses to create 360 degree coverage.

In some embodiments, the cylindrical lenses are stacked in a way suchthat a gap exists between each pair of adjacent cylindrical lenses. Insome embodiments, there is no dielectric material within the gap. Thegaps between the cylindrical lenses allow the cable lines to passthrough the stack of cylindrical lenses structure without obstructingany field of views of the feed elements.

This novel approach utilizes lens technology with radiating elements tocreate directional patterns providing multiple beams for up to 360degree coverage. Specifically, this novel approach allows for thearrangement of lenses in a non-interfering fashion to allow for asystematic assembly of many lenses to support many frequency bands inall directions.

FIG. 1 illustrates an example antenna 100 having a stack of cylindricallens elements. In this example, the antenna 100 includes six cylindricallens elements 105, 110, 115, 120, 125, and 130. Each cylindrical lenselement also includes multiple feed elements disposed along thecircumferential surfaces of the cylindrical lenses. For example, thecylindrical lens element 105 includes two feed elements 135 a and 135 b,the cylindrical lens element 110 includes two feed elements 140 a and140 b, the cylindrical lens element 115 includes two feed elements 145 aand 145 b, the cylindrical lens element 120 includes four feed elements150 a, 150 b, 150 c, and 150 d, the cylindrical lens element 125includes four feed elements 155 a, 155 b, 155 c, and 155 d, thecylindrical lens element 130 includes four feed elements 160 a, 160 b,160 c, and 160 d. As shown, the cylindrical lenses have heights that aresubstantially the same as the heights of the feed elements. Preferably,the cylindrical lenses have heights that are slightly (e.g., less than20% of the heights of the feed elements, preferably less than 10% of theheights of the feed elements, and even more preferably less than 5% ofthe heights of the feed elements) more than the heights of the lenselements.

The feed elements associated with each lens element are configured togenerate RF signals that cover 120 degrees field of view via thecylindrical lens. In this example, the lens elements 105, 110, and 115makes up a first set of lens elements configured to provide RF signalcoverage of a first band (e.g., a low band (698 MHz-960 MHz), etc.). Inthis example, each feed element in the lens elements 105, 110, and 115is configured to provide a distinct 60 degree coverage such that thecombined coverage of the lens elements 105, 110, and 115 issubstantially equal to 360 degrees.

Furthermore, the lens elements 120, 125, and 130 make up a second set oflens elements configured to provide RF signal coverage of a different,second band (e.g., a high band (1,710 MHz-2,690 MHz), etc.). In thisexample, each feed element in the lens elements 120, 125, and 130 isconfigured to provide a distinct 30 degree coverage such that thecombined coverage of the lens elements 120, 125, and 130 issubstantially equal to 360 degrees.

Frequencies and number of beams can be adjusted by using differentradiating elements (feed elements), and adjusting the number of feedelements depending on coverage requirements (number of beams required).Furthermore the required resultant (achieved) beam width and beampattern can be determined by the size (diameter) and shape of thecylindrical lenses.

This approach allows the user to design the type of cylindrical lensrequired (e.g., based on the number of beams radiating through lens,total coverage required, beam-width required, frequency range used,etc.), and combine different cylindrical lenses into one antenna for thedesired coverage.

In some embodiments, the lens elements 105-130 are stacked together suchthat a small gap (e.g., gaps 165, 170, 175, 180, and 185) exists inbetween each adjacent pair of lens elements. Preferably, the gaps arejust large enough to fit a width of the cable (not shown) that connectsthe feed elements to a terminal outside of the antenna, which requiresthe cables to traverses the cylindrical lenses. The gaps between thecylindrical lenses limit the interference typically caused by opposingfeeds/cables/support structures when feeds are placed around a lens for360 degree coverage.

FIG. 2 illustrates the top three lens elements 105, 110, and 115 fromthe antenna 100 in FIG. 1, but with the gaps exaggerated forillustration purposes. Additionally, FIG. 2 shows cables that connectthe feed elements to a signal processor 205. It is noted that each feedelement is required to connect to the signal processor 205 via a cablein order to transmit and receive RF signals. Thus, the cable thatconnects to the feed elements 135 a and 135 b of the cylindrical lens105 is required to traverse cylindrical lenses 110, 115, 120, 125, and130 in order to connect to the signal processor 205.

Instead of traversing the cylindrical lenses 110, 115, 120, 125, and 130by going straight down along the sides (circumferential surfaces) of thelenses, which will inevitably creates interference and obstruction forother lens elements, it is contemplated that the cables can traversethrough the gaps between the cylindrical lenses. As shown, the cables210 and 215 that connect feed elements 135 a and 135 b, respectively, tothe signal processor 205 first runs straight down through thecircumferential surface of the cylindrical lens 105 on the side of thefeed elements 135 a and 135 b so to not obstruct the field of view ofthe lens element 105. The cables 210 and 215 then traverse the gap 165between the cylindrical lenses 105 and 110 across the flat surface ofthe cylindrical lenses 105 and 110 (e.g., the bottom surface of thecylindrical lens 105 and the top surface of the cylindrical lens 110) tothe side of the cylindrical lens 110 where the feed elements 140 a and140 b are disposed, before coming straight down along thecircumferential surface of the cylindrical lens 110 behind the feedelements 140 a and 140 b. Then, the cables 210 and 215 again traversesthe gap 170 between the lens elements 110 and 115 across the flatsurface of the cylindrical lenses 110 and 115 (e.g., the bottom surfaceof the cylindrical lens 110 and the top surface of the cylindrical lens115) to the side of the cylindrical lens 115 where the feed elements 145a and 145 b are disposed so not to obstruct the field of view of thelens element 115, before coming straight down along the circumferentialsurface of the cylindrical lens 115 behind the feed elements 145 a and145 b. The cables 210 and 215 will traverse under this approach throughthe remaining lens elements in the antenna 100 before reaching thesignal processor 205.

Similarly, the cables 220 and 225 that connect feed elements 140 a and145 b, respectively, to the signal processor 205 first runs straightdown through the circumferential surface of the cylindrical lens 110 onthe side of the feed elements 140 a and 145 b so to not obstruct thefield of view of the lens element 110. The cables 220 and 225 thentraverse the gap 170 between the cylindrical lenses 110 and 115 acrossthe flat surface of the cylindrical lenses 110 and 115 (e.g., the bottomsurface of the cylindrical lens 105 and the top surface of thecylindrical lens 110) to the side of the cylindrical lens 115 where thefeed elements 145 a and 145 b are disposed, before coming straight downalong the circumferential surface of the cylindrical lens 115 behind thefeed elements 145 a and 145 b. The cables 220 and 225 will traverseunder this approach through the remaining lens elements in the antenna100 before reaching the signal processor 205.

It is noted that at least a portion of the gaps 165, 170, 175, 180, and185 that are not occupied by the cables, are occupied by anon-dielectric filler.

In some embodiments, a stack of cylindrical lenses with a single feedcolumn can be employed (e.g., for a 120 degree coverage). In such anembodiment, multiple feed elements can be placed on the lens, forexample to create a narrow beam, for use in an array, or to createdistinct multiple beams. In such an embodiment, since each disc wouldtypically be the same height as one element, if two rows of beams (i.e.two rows of elements) are desired (for example, to provide more portcount or to array the elements so the resultant vertical beam width isnarrowed) is possible to stack two sets of cylindrical lenses with theirfeed elements facing the same direction. In such an embodiment, there isno need for spacing to accommodate cabling. In such circumstances thespacing can be filled with filler material. In some embodiments, thespacing in the lens between each feed can be filled with filler material(e.g., a non-dielectric material).

Important features of an antenna assembly/system of the inventiveconcept include:

-   -   The use of stacked cylindrical lenses (dielectric lens discs),        where each lens provides 120 degree coverage (for a required        frequency), with the lenses stacked on top of each other to        create a 360 degree coverage, as opposed to placing feeds all        around the circumference of a single cylindrical lens.    -   Arrangement of the lenses and cabling (with gaps between discs),        with the arrangement of the cabling designed to limit        interference for 360 degree coverage    -   In an antenna/lens system where multiple feeds are in place (for        example in an array), the gap between the feeds can be occupied        with a filler material (which is not necessarily dielectric) in        order to reduce cost. This can be applied to a single lens with        single frequency or for stacked lenses (discs for multiple        frequencies). For example, in a 360° small cell antenna of the        inventive concept, holes between the disc lenses where the        cables run through could be so filled.

It should be appreciated that antennae as described above can beutilized as elements for multi-beam, multi-mode, and/or multi-bandassemblies, where each lens represents a portion of a cylinder that isconfigured for stacking.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the spirit of theappended claims. Moreover, in interpreting both the specification andthe claims, all terms should be interpreted in the broadest possiblemanner consistent with the context. In particular, the terms “comprises”and “comprising” should be interpreted as referring to elements,components, or steps in a non-exclusive manner, indicating that thereferenced elements, components, or steps may be present, or utilized,or combined with other elements, components, or steps that are notexpressly referenced. Where the specification claims refers to at leastone of something selected from the group consisting of A, B, C . . . andN, the text should be interpreted as requiring only one element from thegroup, not A plus N, or B plus N, etc.

What is claimed is:
 1. An antenna for use in wireless communications,comprising: a first sub-antenna, comprising a first cylindrical lens anda first emitter that is coupled to the first cylindrical lens, whereinthe first cylindrical lens and the first emitter are arranged to providea first field of view at a first wavelength; a second sub-antenna,comprising a second cylindrical lens and a second emitter that iscoupled to the second cylindrical lens, wherein the second cylindricallens and the second emitter are arranged to provide a second field ofview at a second wavelength; and a third sub-antenna, comprising a thirdcylindrical lens and a third emitter that is coupled to the thirdcylindrical lens, wherein the third cylindrical lens and the thirdemitter are arranged to provide a third field of view at a thirdwavelength, a cable that is communicatively coupled to the first,second, and third emitters by traversing a first gap between the firstand second cylindrical lenses and a second gap between the second andthird cylindrical lenses, wherein the first, second, and third field ofviews are non-overlapping, wherein the first, second, and thirdsub-antennae are arranged vertically along their respective centralaxes.
 2. The antenna of claim 1, wherein the first, second, and thirdwavelengths are substantially identical.
 3. The antenna of claim 1,wherein each of the first field of view, the second field of view, andthe third field of view is substantially equal to 120°.
 4. The antennaof claim 1, wherein the cable is in contact with a flat surface of atleast one of the first cylindrical lens and the second cylindrical lens.5. The antenna of claim 1, wherein the cable creates no impingement uponthe first, second, and third field of views.
 6. The antenna of claim 1,wherein the cable traverses along the curve surface of the secondcylindrical lens substantially near the second emitter.
 7. The antennaof claim 1, further comprising: a fourth sub-antenna, comprising afourth cylindrical lens and a fourth emitter that is coupled to thefourth cylindrical lens, wherein the fourth cylindrical lens and thefourth emitter are arranged to provide a fourth field of view at afourth wavelength; a fifth sub-antenna, comprising a fifth cylindricallens and a fifth emitter that is coupled to the fifth cylindrical lens,wherein the fifth cylindrical lens and the fifth emitter are arranged toprovide a fifth field of view at a fifth wavelength; and a sixthsub-antenna, comprising a sixth cylindrical lens and a sixth emitterthat is coupled to the sixth cylindrical lens, wherein the sixthcylindrical lens and the sixth emitter are arranged to provide a sixthfield of view at a sixth wavelength, wherein the cable is furthercommunicatively coupled to the fourth, fifth, and sixth emitters bytraversing a third gap between the third and fourth cylindrical lenses,a fourth gap between the fourth and fifth cylindrical lenses, and afifth gap between the fifth and sixth cylindrical lenses wherein thefourth, fifth, and sixth field of views are non-overlapping, wherein thefirst, second, third, fourth, fifth, and sixth sub-antennae are arrangedvertically along their respective central axes.
 8. The antenna of claim7, wherein the fourth, fifth, and sixth wavelengths are substantiallyidentical.
 9. The antenna of claim 8, wherein the first, second, andthird wavelengths are different from the fourth, fifth, and sixthwavelengths.
 10. The antenna of claim 8, wherein the first, second, andthird wavelengths over a low band and the fourth, fifth, and sixthwavelengths cover a high band.